Why do the ICU and long stays concentrate denials?
Long stays concentrate denial (claim denial, total or partial) because they combine three risks that grow every day: more per diems to authorize, more items to justify and more time before the claim is sent. In the ICU, each per diem usually costs more, and the health plan (operadora, the private health insurer) often questions whether the patient still needs intensive care.
For scale: the average length of stay at Anahp hospitals was 3.76 days in 2025 [2]. A three-week stay is therefore far above the benchmark. That alone is not a reason for denial, but it draws the health plan's auditors. More sector indicators are in Industry data.
The causes repeat: per diems beyond the authorized period, progress notes that do not show why the patient remains in the ICU, per diem counts that do not match the recorded dates, and claims assembled only after discharge.
ICU denials are a special case of hospital claim denials: the general rules on contracts, deadlines and appeals apply, and what changes is the proof required for each day of the stay.
The length-of-stay and ICU denial codes
The health plan reports the reason for each denial in the claim review statement, using a message from table 38 of TUSS (Terminologia Unificada da Saúde Suplementar, the unified code set for Brazil's private health sector). Knowing the length-of-stay messages helps prevent denials at the source and build the appeal with the right proof [5].
| TUSS 38 code | Message (summary) | What usually triggers it | Proof that prevents it or supports the appeal |
|---|---|---|---|
| 1903 | Length of stay inconsistent with clinical progress | Brief or copy-paste notes, no treatment plan | Daily notes with condition, management and reason to stay |
| 1904 | Length of stay inconsistent with the authorized procedure | Days beyond what was expected for the authorized procedure | Extension request describing the complication |
| 1911 | Hospital stay for unjustified investigation (effective 12/01/2025) | Stay kept only for tests that could be outpatient | Clinical reason to investigate as an inpatient |
| 3194 | Item inconsistent with the diagnosis or clinical progress (effective 12/01/2025) | Stable patient, no intensive support documented | Record of ongoing support (ventilation, vasoactive drugs, monitoring) and ICU discharge criteria |
| 1910 | Per diems for different accommodations on the same day (effective 12/01/2025) | ICU and another unit's per diem billed on the transfer day, or a count that does not match admission, transfer and discharge dates | Dates and times checked before submission |
| 1917 | No extension for the number of per diems billed (effective 12/01/2025) | Extension not requested or denied | Extension form with authorization number and authorized period |
| 3188 | Care item billed during an unauthorized stay (effective 12/01/2025) | Supplies and drugs on days with no extension | Authorized extension covering the period |
| 3189 | Care item quantity inconsistent with the length of stay (effective 12/01/2025) | Consumption above what is expected for the recorded days | Daily orders and nursing administration records |
The key point: denying an unauthorized per diem drags down what was used that day, through messages 3188 (item during an unauthorized stay) and 3189 (item quantity inconsistent with the length of stay) [5]. The full list is in the guide TISS denial codes, and per diem composition rules are in Daily rate and fee denials.
What does the law guarantee in a long stay?
The law guarantees coverage of inpatient care with no time limit; the contract defines how each day is authorized and billed. Article 12, II, “a” and “b” of Lei 9.656/1998 forbids limiting inpatient stays and stays in an intensive care unit or similar by time, maximum amount or quantity, with ICU care at the attending physician's discretion [3]. Brazil's Superior Court of Justice (STJ) held in Súmula 302 (a binding summary of case law) that a health plan clause limiting the length of an inpatient stay is abusive [11].
That does not stop the health plan from auditing. RN 503/2022 (Normative Resolution 503/2022) of ANS, Brazil's National Agency for Supplementary Health (the private health plan regulator), requires the hospital–health plan contract to set the audit routine, the grounds for denial and the deadlines to appeal, to respond and to pay after a reversal [7]. The same contract must identify which procedures need authorization [7].
In practice, each period must be authorized under the contract and justified in the medical record. Coverage at the start of the stay is covered in the guide Prior authorization.
Extensions: the right form, before the authorization expires
An extension is the formal request to continue the stay beyond the authorized period. TISS (Troca de Informações na Saúde Suplementar, Brazil's mandatory health data exchange standard) has a dedicated form for this, which carries the number of the original admission request [4]. The inpatient summary, which bills the stay, also references that request [4].
Under TISS, electronic authorization is optional, while admission and discharge notices are mandatory [4]. The channel and how often reports are due vary by health plan and should be in the contract.
| Question | Where the answer is | Risk if nobody answers it |
|---|---|---|
| How many days does the admission authorization cover? | The health plan's reply to the request | Per diems billed beyond the authorization (1917) |
| How far ahead should the extension be requested? | Contract or health plan provider manual | Request made after expiration |
| Which report goes with the request, and how often? | Contract or health plan provider manual | Extension denied for lack of justification |
| What is the health plan's response deadline? | Contract, under RN 503/2022 [7] | Patient stays without defined coverage |
The practical rule is to request the extension before the authorized period ends, with an updated clinical report, and to record the protocol number. The step-by-step is in the guide Inpatient stay extension.
What must the medical record prove to justify the stay?
The medical record must prove, day by day, why the patient cannot be discharged or leave the ICU. Resolution 1.638/2002 of the CFM (Federal Council of Medicine) lists daily progress notes, with date and time, signature and medical license number, among the mandatory items of the record [10]. A note that only repeats “patient stable, same plan” does not support an ICU per diem.
A progress note that survives the audit usually answers four questions:
- What is the condition today? Vital signs, tests and changes from the previous day.
- What intensive support is ongoing? Mechanical ventilation, vasoactive drugs, dialysis, invasive monitoring or other support that requires the bed.
- What prevents discharge or transfer? An objective clinical criterion, not an undocumented “waiting for a bed”.
- What is the plan? Treatment goal and next reassessment.
Nursing completes the proof with administration records for each ordered item and the times in each unit. A stay for non-clinical reasons, such as waiting for a bed, should be recorded as such and handled under the contract. The guide Medical record audit details what each professional must document.
Concurrent review: auditing the claim while the patient is still in the hospital
Concurrent review is the audit done during the stay, not after discharge. In a long stay, it is the front that most reduces denials, because it fixes documentation and authorization gaps while there is still time.
CFM Resolution 2.448/2025, which revoked Resolution 1.614/2001, lists among the physician auditor's rights the audit during the stay and on-site access to the medical record, without removing it or making copies (art. 10) [8]. That article is not among those marked as suspended by a court decision in the official text checked on 10/17/2026 [8]. For nursing, Resolution 720/2023 of Cofen (Federal Nursing Council) limits the nurse auditor's access to the facility's premises during concurrent or retrospective review [9].
Inside the hospital, internal concurrent review follows a daily routine:
| Daily check | Owner | Denial it prevents |
|---|---|---|
| Authorized period vs. days in the hospital so far | Billing or authorization center | 1904, 1917, 3188 |
| Physician notes with condition, support and plan | Internal physician audit | 1903, 1911, 3194 |
| Dates and times of admission, transfer and exit from each unit | Nursing and billing | 1910, 3189 |
| Items ordered vs. administered vs. posted to the claim | Internal nursing audit | 3189 and supply and drug messages |
| Open items with the health plan auditor (visit, report, opinion) | Billing coordination | Clinical denial at closing |
The differences between review types are in the guide Prospective, concurrent and retrospective review.
How daily control of a long stay works
Daily control brings the three fronts together in a cycle that repeats until discharge:
See the steps as a table
| Step | What to do | Denial it prevents |
|---|---|---|
| 1. Check the period | Authorized period and days left until the authorization number expires | 1904, 1917 |
| 2. Review notes and items | Concurrent review of the day | 1903, 1911, 1912, 3189 |
| 3. Request the extension | Before it expires, with a clinical report | 1917, 3188 |
| 4. Close the interim bill | For the period set in the contract | 1914 (cut-off dates) |
| 5. At discharge: final bill | With dates and times checked | 1914 |
- Check the authorized period and how many days are left before the authorization number expires.
- Review the day's notes and items (concurrent review).
- Request the extension before it expires, with a clinical report, and record the protocol number.
- Close the interim bill when the contracted period ends.
- At discharge, close the final bill, with the dates checked.
When should a hospital send an interim bill?
An interim bill charges one period of the stay while the patient is still in the hospital. TUSS table 55 (billing type) has four options: partial, final, supplementary and total [6]. How often an interim bill is sent, however, is not set by ANS: it depends on the contract, which under Lei 9.656/1998 must set billing and payment deadlines and procedures [3].
In a long stay, interim billing shortens the review, brings forward the denial of one period (which helps fix the next ones) and avoids carrying weeks of unbilled cost.
The risk lies in the handoff between bills, with duplicated or missing per diems: each interim bill should close with a clear cut-off date and time. The guide Interim billing details the workflow.
What we see in operations
At Accrua, long stays are followed while the patient is still in the hospital, not only after discharge. Accrua OS reads the open claim: daily charges posted, authorization number and extension validity, clinical progress notes that justify the ICU stay. Each day is checked against the contract, the authorization rule and that health plan's denial history for daily rates and length of stay.
When a day's progress note is missing or an extension is about to expire, the task goes to whoever can solve it, with the source shown. In our managed operation, auditors with nursing backgrounds check whether the clinical record supports each daily charge, because that is what the health plan will ask.
For long stays, we work with the hospital on when to bill an interim claim, as the contract allows. And because the ICU concentrates value and time, Receita Garantida can put the value of eligible production into the hospital's account when it needs it.
Where to start
- List current stays longer than seven days and check, for each one, the authorized period and the date the authorization expires.
- Gather each health plan's extension rules (lead time, report, frequency) and make them visible to the team.
- Set up a daily review of progress notes for ICU stays, using the four questions in this guide.
- Track denials by length-of-stay code (1903, 1904, 1910, 1911, 1917, 3188, 3189) over the last 12 months, by health plan.
- Negotiate interim billing frequency in contracts that do not yet provide for it.